The invention relates to a method for preparing a hydraulically settable cement base material starting from steel slags formed in a steel-making process.
Steel slags have hitherto mainly been used solely as a filler in a road-building material.
Although there is a silicate and an aluminate fraction present in steel slags, binding properties of steel slags when used as aggregate in concrete have never been observed.
However, steel slags contain several mineral fractions which are important for application as binders:
alite: C3S PA1 belite: C2S PA1 celite: C3A PA1 brownmillerite: C4AF
where C=CaO, S=SiO.sub.2, A=Al.sub.2 O.sub.3 and F=Fe.sub.2 O.sub.3.
Steel slags usually contain much C3S, C2S and C4AF, but little C3A. The large amount of ferrites, in particular, has, however, proved disadvantageous in rendering the slag material suitable for use as a hydraulic binder.